Her uniform looks good, with striped scarf and blue cap in perfect order, but railway employee Mitsue Endo has one thing to do before she faces the masses — pass the smile test.

Endo, who works at hectic Shinagawa Station in central Tokyo for Keihin Express Railway Co., sits in front of a laptop computer with a digital camera mounted on top. At first she is a bit grim-faced, and the verdict from the company's smile-rating software is instant and candid.

"Smile: 0" pops up on the screen.

She breaks into a broad grin and the computer responds cheerfully, giving her a score of 70.

The company has installed the system to help employees check their smiles before heading out to face customers. The test is optional, but at major stations like Shinagawa, the 250,000 riders who pass through per day can be rushed and agitated, and a happy face can go a long way.

"Smiling helps our interaction with the passengers. I think the atmosphere becomes more relaxing with a smile," says Endo, whose job includes helping lost customers find their way and dealing with ticketing mishaps.

Keihin uses the software at 15 of its 72 stations, concentrating on the busier locations.

Taichi Takahashi, who works in public relations at the train operator, says it gives employees a chance to examine themselves before they go to work.

"I don't think that we have had much opportunity to stare at our faces that close and for that long to check our facial expressions until now," he said.